Brown Margins Research Articles

Mycosphaerella macrospora . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Mycosphaerella macrospora . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Iris, Glodiolus ; also recorded from Narcissus, Freesia and Hemerocallis . DISEASE: Leaf spot or blotch of iris. Initially, symptoms appear as small water-soaked spots soon turning brown and enlarging to produce oval lesions with a greyish centre and dark brown margin. These become irregular and coalesce and may destroy much of the leaf tissue. The disease is most serious after flowering and on the distal portions of leaves. GEOGRAPHICAL DISTRIBUTION: Europe, North America, South Africa, Australia and Middle East. TRANSMISSION: Conidia are dispersed by wind and rain. Overwintering infected leaf debris is an important source of spring inoculum. The perfect state appears to be uncommon.

Pseudocercosporella herpotrichoides . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Pseudocercosporella herpotrichoides . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Wheat, barley, oats, rye. Also occurs on many wild and cultivated grasses, including Aegilops, Agropogon, Agrostis, Alopecurus, Bromus, Dactylis, Festuca, Koeleria, Lolium and Poa spp. DISEASE: Causes eyespot of cereals. Typically the disease is characterized by a pale oval spot with a brown margin on the basal leaf sheaths and culm of cereal tillers at or just above ground level, but such symptoms maybe obscure on some cereals, e.g. oats. Black, stromatic pustules are often present within the centre of the lesion and stems may be ridged, kinked, frayed or otherwise distorted at the diseased zone. The grey mycelium of P. herpotrichoides can often be seen in the internal cavity of straws when they are split open. Random lodging ('straggling') of diseased crops occurs as diseased straws topple over before harvest; storm lodging is also more severe. Eyespot symptoms also include a culm or foot rot which can result in post emergence death of young seedlings or tillers; shrivelled grain and partially empty ears (whiteheads) can also occur on maturing crops. GEOGRAPHICAL DISTRIBUTION: Widespread throughout Europe; also occurs in some areas of N. America, Africa and Australia and in New Zealand (CMI Map 74, ed. 3, 1969). TRANSMISSION: Survival of the fungus between crops occurs on infected plant debris, particularly old stubble. Conidia are produced abundantly on this in wet autumn and spring weather and infect the leaf sheaths of young winter cereals. Direct mycelial infection can also occur. The fungus can survive long periods in the soil in infected crop debris and can infect susceptible crops planted at intervals of several years. Secondary weed hosts also act as a source of the fungus but are not as important as old stubble (49, 2426). During moist, cool springs secondary infection within a crop can occur by conidia dispersed from diseased plants.

Drechslera incurvata . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Drechslera incurvata . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cocos nucifera . DISEASE: A leaf spot of young coconut ( Cocos nucifera ). The spots are at first small, oval, brown; enlarging and becoming pale buff in the centre with a broad, dark brown margin. In severe attacks the edges of leaves become extensively necrotic. GEOGRAPHICAL DISTRIBUTION: Apart from records from Jamaica and Seychelles the fungus has been reported only from S.E. Asia, Australasia and Oceania: British Solomon Islands, Fiji, French Polynesia, Malaysia (W., Sabah, Sarawak), New Caledonia, New Hebrides, Papua-New Guinea, Philippines, Sri Lanka, Vietnam and Thailand. TRANSMISSION: Presumably air dispersed.

日本産ノサシバエの種名について

In order to revise the specific name of Haematobia found in Japan, we examined and compared whole the available material with the specimens of Haematobia exigua captured in Nepal and Taiwan, and Haematobia irritans taken in Europe and Hawaii. From the opinions of the previous authors quoted in this paper, as well as from our own findings, it seems reasonable to concluded herein that irritans and exigua are distinguishable and the Haematobia of Japan is irritans. Reliable characters to distinguish exigua from irritans may be as follows : 1) In the male of exigua the second segment of the hind tarsi bears 4 to 6 very long hairs with curled tips on the posterior margin, whereas in irritans it has only one long hair on the distal end. 2) The basal bristle on the ventral surface of the hind femur is always brown, long and strong in irritans, whereas it is pale, short and weak in exigua. 3) The acrostichal hairs tend to be more regularly arranged in fewer rows (4 rows) in exigua than in irritans (5-6 rows). 4) The color of the female palpi is generally brownish in irritans, but yellowish in exigua. 5) The lower squamae are white with light brown margins in exigua, but those are light brown with dark brown margins in irritans. 6) The color of the thoracic hairs and frontal bristles are usually yellow to light brown in exigua, but brown to blackish brown in irritans. 7) It is difficult to settle one specimen to irritans or exigua based on the number of frontal bristles, but this character can be applied to separate a population to irritans or exigua. 8) Likewise the measurement of body length appears to be useful to sort out a population to irritans or exigua.

Pestalotiopsis theae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Pestalotiopsis theae . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Camellia sinensis ; also recorded on Cocos, Diospyros, Elaeis, Gossypium, Mangifera, Syzgium, Theobroma and a number of other unrelated hosts. DISEASE: Grey blight of tea, which begins as small brown spots on the leaves, later enlarging to 1 cm diam. or more and showing (on the upper surface) a greyish centre with light to dark brown margins. Lesions are usually circular or oval with concentric zonations marked out on the upper surface by the dark acervuli. On young leaves these zonations are often absent. Coalescence of the spots may occur. GEOGRAPHICAL DISTRIBUTION: Australia, Azores, Brazil, Burma, Ceylon, China, Canary Island, Ethiopia, Formosa, Ghana, Guinea, Hawaii, Hong Kong, India, Indonesia, Iran, Japan, Kenya, Laos, Malagasy Republic, Malawi, Malaysia, Mozambique, Nepal, Papua New Guinea, Peru, Rhodesia, Sierra Leone, Somaliland, S. Africa, Tanzania, Thailand, Turkey, Uganda, USSR, Vietnam (S.). TRANSMISSION: No detailed studies reported; the spores may be soil-borne (40: 184).

Growth Response of Greenhouse Chrysanthemum, Chrysanthemum morifolium, to Root Drenches of Diazinon and Demeton1

Root drenches of diazinon and of demeton on greenhouse chrysanthemum were compared for growth-response effects in plants grown in complete and phosphorus deficient nutrient solutions. Drenches of diazinon resulted in different degrees of inhibition of plant growth. Analysis of soil showed no detectable differences in phosphorus (P) content because of diazinon treatment. Plants grown in sand culture and treated with demeton showed symptoms of phytotoxicity expressed as brown margins of lower leaves 1 week following treatments of 32, 64, 128 pounds per acre in both nutrient solutions. Later, plants showed significant growth inhibition in complete nutrient solutions at 128 pounds per acre, while an increase in growth was observed with a P-deficient nutrient solution. However, this effect was less than that observed in the controls with complete nutrients. Application of a fixed amount of demeton to plants grown under certain element deficiencies indicated that the growth response obtained is associated only with P deficiency. Attempts to correlate this increase in growth with the P in the insecticide and that in the leaf tissue were unsuccessful. It is suggested that the growth-response effects associated with diazinon and demeton treatments reported in the literature may be attributed to other factors such as changes in soil fauna and flora, including nematodes, insects, fungi, and bacteria.

Septoria chrysanthemella . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria chrysanthemella . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Chrysanthemum indicum, C. japonicum, C. morifolium, C. parthenium . Also by inoculation on C. azaleanum, C. koreanum, C. leueanthemum, C. segetum, C. roseum, Tagetes patula, Centaurea cyanus (Punithalingam & Wheeler, 1965; Schneider, 1959). DISEASE: Formerly known as brown leaf spot or blight (Halsted, 1891; Cavara, 1892; Salmon, 1907; Moore, 1959) but now referred to as the black leaf spot of chrysanthemum (Hemmi & Nakamura 1927; Waddel & Weber, 1963) in order to distinguish the symptoms from those produced by Septoria obesa (CMI Descript. 139). The first visible leaf symptom is a small discrete necrotic spot. This gradually develops into a circular or elliptical spot seldom irregular, about 5-10 mm wide, at first dark brown, then turning black. Leaf spots of a purple to brown colour, with a distinct brown margin are not uncommon. The disease appears in susceptible chrysanthemum plants of all ages, first on the lower leaves and then gradually progressing upwards. This is a disfiguring disease and in a severe attack all leaves wither resulting in premature defoliation. GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Kenya, Malawi, Mauritius, Mozambique); Asia (China, Formosa, Japan, Pakistan, Philippines); Australasia (Australia, New Zealand); Europe (Austria, Azores, Bulgaria, Cyprus, Czechoslovakia, Denmark, France, Germany, Iceland, Italy, Norway, Portugal, Rumania, Spain, Yugoslavia, U.S.S.R.); North America (Canada, U.S.A.), Central America (Costa Rica, Cuba). (Literature; Herb. IMI). TRANSMISSION: Dimock & Allyn (24: 192) suggested the pathogen may survive the winter in the soil in infected debris from the previous season. The fungus may be disseminated by water splash or by mechanical means as with S. obesa .

On the bacterial leaf spot of alfalfa

The bacterial leaf spot of alfalfa caused by Xanthomonas phaseoli f. sp. alfalfae was observed for the first time in Japan at the farm of National Institute of Animal Industry, in September 1962.Leaf spots are at first minute, round, watersoaked. Mature spots 2-3mm in diameter are pale yellow with a dark brown margin surrounded by a yellowish halo. The spots tend to coalesce along midrib and near the tip or the margin of the leaflets. Severely infected leaves often shed.The causal bacteria infected Phaseolus vulgaris by inoculation producing symptom similar to that produced by Xanthomonas phaseoli on the same host.The morphological, cultural and phsiological characters of the bacteria causing the disease were investigated, and hardly distinguishable from those described by Riker et al. (1935) and Sabet (1959).Therefore the causal bacteria were quite identical in all its characteristics with Xanthomonas phaseoli f. sp. alfalfae (Riker, Jones et Davis) Sabet.

OCULAR VARICELLA

The ocular complications of varicella (chickenpox) are rare indeed. This impression is supported by the sparsity of the ophthalmic literature dealing with the disease. Conjunctival vesicles 1 exhibiting phlyctenualr-like pustules 2 have occasionally been reported to invade the cornea. These may develop into ulcer excavations 3 with swollen, reddish brown margins. Minimal edema of the lids 4 is also frequently demonstrable. Corneal complications are more infrequent. A direct corneal lesion is most unusual but may appear relatively late in the course of the disease. Oppenheimer, in 1905, 5 reported a case of a vesicular lesion which developed into a shallow ulcer. Pickard, 6 in 1936, reported a case of interstitial infiltration with associated endothelial changes. Rosenbaum, 7 in 1943, described a similar case in which was exhibited a shallow central corneal ulcer with minor infiltration of Descemet's membrane and the endothelium. Superficial keratitis has been associated with chickenpox. In a